Palm tree peroxidase-based biosensor with unique characteristics for hydrogen peroxide monitoring

Three amperometric enzyme electrodes have been constructed by adsorbing anionic royal palm tree peroxidase (RPTP), anionic sweet potato peroxidase (SPP), or cationic horseradish peroxidase (HRP-C) on spectroscopic graphite electrodes. The resulting H2O2-sensitive biosensors were characterized both in a flow injection system and in batch mode to evaluate their main bioelectrochemical parameters, such as pH dependency,I-max, K-M(app), detection limit, linear range, operational and storage stability. The obtained results showed a distinctly different behavior for the plant peroxidase electrodes, demonstrating uniquely superior characteristics of the RPTP-based sensors. The broader linear range observed for the RPTP-based biosensor is explained by a high stability of this enzyme in presence of H2O2. The higher storage and operational stability of RPTP-based biosensor as well as its capability to measure hydrogen peroxide under acidic conditions connect with an extremely high thermal and pH-stability of RPTP. (c) 2005 Elsevier B.V. All rights reserved.